*{
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
.container{
    width: 100%;
    margin: 0 auto;
    height: 100px;
    background-color: skyblue;
    max-width: 100%;
    padding: 20px;
    .middle{
        width: 1200px;
        height: 100%;
        background-color: red;
        margin: 0 auto;
        max-width: 100%;
    }
}